Spectroscopy of GaAs quantum wells

Technical Report · Mon Jul 01 00:00:00 EDT 1985

DOI:https://doi.org/10.2172/5970233· OSTI ID:5970233

West, L C

A new type of optical dipole transition in GaAs quantum wells has been observed. The dipole occurs between two envelope states of the conduction band electron wavefunction, and is called a quantum well envelope state transition (QWEST). The QWEST is observed by infrared absorption in three different samples with quantum well thicknesses 65, 82, and 92 A and resonant energies of 152, 121, and 108 MeV, respectively. The oscillator strength is found to have values of over 12, in good agreement with prediction. The linewidths are seen as narrow as 10 MeV at room temperature and 7 MeV at low temperature, thus proving a narrow line resonance can indeed occur between transitions of free electrons. Techniques for the proper growth of these quantum well samples to enable observation of the QWEST have also been found using (AlGa)As compounds. This QWEST is considered to be an ideal material for an all optical digital computer. The QWEST can be made frequency matched to the inexpensive Carbon Dioxide laser with an infrared wavelength of 10 microns. The nonlinearity and fast relaxation time of the QWEST indicate a logic element with a subpicosecond switch time can be built in the near future, with a power level which will eventually be limited only by the noise from a lack of quanta to above approximately 10 microwatts. 64 refs., 35 figs., 6 tabs.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5970233
• Report Number(s): UCRL-53681; ON: DE86009612
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted. Thesis
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
GALLIUM ARSENIDES
POTENTIALS
QUANTUM MECHANICS
ABSORPTION SPECTRA
ENERGY GAP
EXPERIMENTAL DATA
INFRARED RADIATION
NONLINEAR PROBLEMS
OPTICAL COMPUTERS
OSCILLATOR STRENGTHS
ARSENIC COMPOUNDS
ARSENIDES
COMPUTERS
DATA
ELECTROMAGNETIC RADIATION
GALLIUM COMPOUNDS
INFORMATION
MECHANICS
NUMERICAL DATA
PNICTIDES
RADIATIONS
SPECTRA
656000* - Condensed Matter Physics
360603 - Materials- Properties